This study investigated the optimum conditions to maximize the inactivation of biofilms using both plasma-treated solutions and post-treatment storage conditions. Chemical properties of plasma-treated solutions were also analyzed to identify their possible biofilm inactivation mechanisms. Escherichia coli O157:H7 biofilms on stainless steel were prepared and immersed in distilled water (DW), 100 ppm of sodium chloride solution (NaCl), or 100 ppm of sodium hypochlorite solution (NaOCl), followed by container-type plasma treatment for 10 min (15 kHz and 250 W). After plasma discharge was switched off, biofilms immersed in the plasma-treated solution were stored for 10 min with the plasma apparatus closed or open. The log reduction of E. coli O157:H7 was NaOCl (3.58) > NaCl (2.06) = DW (1.95) in the closed storage condition. In addition, the bactericidal effect of NaOCl was higher in the closed condition than in the open condition. Concentrations of the hydroxyl radical (OH·) and peroxynitrite (ONOO−) were also the highest for NaOCl in the closed condition. Consequently, plasma treatment using NaOCl solution in the closed condition was found to be the optimum method for inactivation of E. coli O157:H7 biofilms, due to high hydroxyl radical and peroxynitrite concentrations. This method also has the merit of using a lower concentration of NaOCl than that used typically in industry.

This study investigated protein digestibility of beef puree in infant and adult in vitro digestion models. The simulated digestive juices for infant and adult were prepared. Protein digestibility of beef puree was calculated in the gastric and gastrointestinal compartments. The 10% trichloroacetic acid soluble nitrogen and αamino group contents of gastric digesta were lower in the infant in vitro digestion model than those in the adult in vitro digestion model (p<0.05). In addition, the gastrointestinal digesta from the infant in vitro digestion model had lower value of the 10% trichloroacetic acid soluble nitrogen and α-amino group contents than those of the adult in vitro digestion model (p<0.05). The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the remarkable bands of actin and myosin light chain B were found in the digesta of beef puree from the infant in vitro digestion model. The results of this study revealed the lower protein digestibility of beef puree in infants compared to that in adults. Therefore, the development of ways to increase digestibility of meat protein can improve the nutritional quality of meat products for infants.

The microbial and physicochemical properties of brown and white cooked rice treated by atmospheric pressure plasma (APP). APP was produced (250 W, 15 kHz, ambient air) and applied to brown and white cooked rice for 5, 10, and 20 min. The 20-min plasma treatment reduced in bacterial counts by 2.01 log CFU/g when cooked rice were inoculated with or O157:H7. The pH of the brown cooked rice was decreased by the 5-min plasma. The hardness values of APP-treated brown and white cooked rice were lower than untreated samples. The reducing sugar contents of brown and white cooked rice were significantly higher than those in untreated samples. Lipid oxidation of APP-treated brown and white cooked rice were higher compared to untreated samples. These results indicate that APP improves microbial quality, although further studies should be conducted to change the physicochemical qualities of brown and white cooked rice induced by APP.

Phenolic acids, found in cereals, legumes, vegetables, and fruits, have various biological functions. We aimed to compare the antihypertensive potential of different phenolic acids by evaluating their ACE inhibitory activity and cytoprotective capacity in EA.hy926 endothelial cells. In addition, we explored the mechanism underlying the antihypertensive activity of sinapic acid. Of all the phenolic acids studied, sinapic acid, caffeic acid, coumaric acid, and ferulic acid significantly inhibited ACE activity. Moreover, gallic acid, sinapic acid, and ferulic acid significantly enhanced intracellular NO production. Based on the results of GSH depletion, ROS production, and MDA level analyses, sinapic acid was selected to study the mechanism underlying the antihypertensive effect. Sinapic acid decreases endothelial dysfunction by enhancing the expression of antioxidant-related proteins. Sinapic acid increased phosphorylation of eNOS and Akt in a dose-dependent manner. These findings indicate the potential of sinapic acid as a treatment for hypertension.

A series of experiments were conducted to determine the possibility of using sea tangle powder (STP) and/or its combination with high pressure (HP) as substitutes for phosphate in emulsion‐type sausages. The sausages with STP (1.5% and 3%) had similar cooking loss to sausages with 0.2% sodium pyrophosphate (PC), without a negative effect on overall acceptability, except for texture property, which was inferior to PC (p < 0.05). Instrumental texture properties of sausages containing 3% STP were improved by HP (100 MPa) treatment. Furthermore, the sausages treated with a combination of STP and HP showed similar or greater antioxidant and antimicrobial effect than that of PC. Therefore, a combination treatment of STP and HP could be used effectively as an alternative to phosphate in emulsion‐type sausages because of their similar water holding capacity and instrumental hardness, and greater inhibition ability against lipid oxidation and bacterial growth compared with those of PC. Practical applications Meat industry has been challenged by the increasing consumer's demand for safe and high‐quality meat and meat products. Particularly, the rapid increase of the concept of all‐natural and clean‐label makes manufacturers produce synthetic additive‐free products. However, effective natural alternative for phosphate (synthetic additives) has not been introduced so far. Therefore, this study was conducted to evaluate the potential of combinational use of sea tangle powder and high pressure as an alternative to phosphate in emulsion‐type sausage. Results revealed that this method was effective to replace the addition of phosphate and can be applied directly for industry.